This invention relates to shaving implements and in particular to electric shavers.
There are numerous types of electric and manual implements on the market today for removing or trimming hair present on various skin areas, especially hair on faces of men and on legs of women. Conventional manual razors have a handle with one or more straight razor blades at an upper end. Often these razors are designed to be entirely disposed of after a period of use, or the blade section of the razor is intended for disposal and replacement (with the handle being used more permanently). Such manually moved razors are suitable to be used when the skin is wet, and often when the skin is treated with a shaving cream, soap or lotion. However, the effectiveness of such shavers is limited by the ability of a human hand to manipulate the shaver head.
Well-known conventional electric shavers have rotating or reciprocating blades disposed beneath a perforated screen through which the individual hairs must pass to be cut during shaving. The need for the protective screen can lead to a less consistent and “close” shave, unless various complex and costly techniques are employed to correct this problem. In any case, such electric razors are ordinarily unsuitable for use with conventional shaving creams, and many are not designed for use in a wet environment such as a shower. This latter restriction is of particular concern as many women prefer to shave their legs during their shower.
There also exist some types of hybrid shavers which combine some benefits of manual razors and some of electric shavers. Specifically, these hybrid shavers can be used with shaving cream in a wet environment, while also using electric power to more rapidly move the shaving blade.
Examples of such shavers include U.S. Pat. Nos. 4,744,144, 4,819,330, 4,914,816, 5,046,249 and 5,299,354. The disclosures in these patents, as well as all that in other patents cited herein, are hereby incorporated by reference as through fully set forth herein.
Some of these disclose a shaver having a handle or body containing an electric oscillator or vibration inducing component and to which is attached a straight bladed razor cartridge. Others disclose vibrating shavers having switch-operated and battery-powered DC motors.
In some hybrid shavers, e.g. U.S. Pat. No. 5,007,169, the shaver directly couples a stem of a shaver head to the motor shaft. Others, e.g. U.S. Pat. Nos. 3,611,568; 5,046,249 and 6,105,252, impart oscillatory motion to the razor head without direct coupling to the motive means. This can be done, for example as disclosed in U.S. Pat. Nos. 5,299,354 and 6,105,252, by eccentrically mounting a weight to the rotatable motor shaft.
Rotation of the shaft causes off-center rotation of the weight which in turn imparts oscillatory motion to the razor blade(s). This motion can be passed through a unitary neck extending between the main body of the housing and the razor head, as disclosed in U.S. Pat. Nos. 3,636,627; 5,299,354 and 6,481,104. As disclosed in U.S. Pat. No. 6,421,918, the motion can even be in the ultrasonic range.
These hybrid shavers typically employ an oscillating pattern for their shaving heads. Some, like those in U.S. Pat. No. 3,636,627, use an essentially circular pattern, while others essentially sweep side to side. Significant side to side motion tends to increase the risk of cuts, particularly when the tolerances of manufacture are not precise.
U.S. Pat. No. 6,481,104 discloses a primarily front to back (towards and away from the skin) motion by locating the vibration axis of the weight parallel to the razor blades. However, the means of achieving this motion is costly. Further, the vibration rates of the '104 patent impart an uncomfortable feel to the user's hand.
The art therefore still desires improved assemblies for shaving human skin, where the shaving is effective, and can be achieved in a wet environment using conventional shaving creams and gels.